@KT66: What do you expect as answer from people in a rockox thread?
There has to be something about it if so many talk about it.
Here is the "Why rockbox?" page:http://www.rockbox.org/wiki/WhyRockboxEdited by cholero - 3/11/15 at 10:08am

Can you move your music out of the MUSIC folder to the root of the sd card? That'll probably fix it. Don't have my unit handy, but I vaguely recall there's some way to point the database at a specific folder for situations like yours, but don't know. Did it used to work properly with the files in the MUSIC folder? I don't use the database, so can't be of much help in the long run.